Usually individuals are identified by authentication with the aid of a password. In particular, an individual is identified when he wishes to gain access to confidential data in order to ensure the security of such data. The passwords thus used form part of the knowledge of the user.
It is also possible to improve the security of access to these data by using a medium external to the user, for example a microprocessor card, notably a bank card, on which the password of the user is stored and which makes it possible to verify what the user knows. In this case, the user knows his password, he enters it on a numeric keypad, for example a keypad of a computer terminal, and the microprocessor card makes it possible to compare the sequence input by the user with the encrypted password that is stored on the microprocessor card.
The drawback of passwords is that they can be stolen, or a person can take the place of the person who holds the password. Moreover, the external medium which stores the encrypted password of the user is no longer sufficient to ensure access to the confidential data of the user, since the password may also be stolen and be used fraudulently.
Another drawback is that another person can take the place of the user by knowing the password and by having, fraudulently or not, the microprocessor card of the user. This drawback arises directly from the fact that the password is not intrinsically linked to the individual, since several people can be authenticated with a single password.
In order to improve known authentication systems, biometric systems are currently used. The biometric data are data intrinsic to the individual and can solve some of these problems.
There is currently retinal recognition or fingerprint recognition. However, these devices are complex and require highly-developed processing algorithms in order to process the considerable mass of data that a retina or a fingerprint can provide.
Moreover, fingerprints can be reproduced. Another drawback of fingerprint recognition is that the end of the finger can be covered with a thin layer of deposit, such as a layer of grease which can disrupt the measurement systems.
Another drawback of the current biometric systems is that it would be possible to force a person to place his retina, or his fingers, in front of the authentication systems and thus force access to the data of the user.
It is therefore proposed, in particular, to provide a means for identifying an individual that is less complex than those cited above and that could improve the security of access to the data of the user.